Hello guys hope we had a nice week, and hope we enjoyed the last post, this is a post concentrated on how to build an automatic night lamp that comes on itself at night and goes off itself when its day time.
The diagrams of all the components used is shown above and the circuit diagram plus explanation is shown below.
This is the circuit diagram for the night lamp and if you want to get the darkness level for the light to come on automatically you cover the surface of the ldr then vary the 10k resisresistor till you get your desired darkness level and the lm393 IC can only give an output when the voltage on the positive side is more than the reference voltage set from two fixed value resistor and a multimeter can be used to measure the output voltage from the first voltage divider circuit going to the pin 2, then when the voltage is more than the voltage available at pin3 it gives an output on pin1. we would have used a variable also at the second voltage divider circuit but to reduce stress we used a fixed resistor and the default reference voltage will be 2.5volts due to the power being 5volts so the two resistors reduced it to 2.5v, you could increase the voltage used in powering the whole circuit if you want but make sure your DC bulb can handle the voltage .
Then the resistor acts as an amplifier to amplify the power coming from the comparator due to the comparator being a low power type to power the bulb convenient my and to get something bright.
Introduction
This is a blog post centered around how to build an automatic night lamp based on a comparator IC named (lm393) and some other circuitary will be added to make the circuit capable of lighting a DC bulb bright enough to light a room and this lamp comes on itself when there is darkness and goes off when there is light, and this can be employed in home security automation to reduce stress and removed the pain of having to switch on and off your security light yourself.
Lm393
This is a dual comparator IC that gives an output based on the voltage compared with the reference voltage. And it only gives an output when the positive voltage is higher than the negative voltage which is the reference voltage. And this chip is low powered and has a wide input voltage range between 1v and 36v and this IC can do far more than just night lamp, it can also be used industrially and can be used to control battery charging and lots more.
Comparator
A comparator is a device that compares two input, but defining it electrically is to say that a comparator is any device capable of comparing two input voltages and give an output voltage .
Materials needed
1. Lm393 ic
2. Ldr ( light dependent resistor).
3. 10k variable resistor
4. 1k fixed resistor 2piece.
5. Non transistor (bc547)
6. 10k resistor 1piece
Circuit diagram and explanation.
Sorry In the above circuit the place I wrote 3 is supposed to be 2 and the place I wrote 2 is suppose to be 3
This is the circuit diagram for the night lamp and if you want to get the darkness level for the light to come on automatically you cover the surface of the ldr then vary the 10k resisresistor till you get your desired darkness level and the lm393 IC can only give an output when the voltage on the positive side is more than the reference voltage set from two fixed value resistor and a multimeter can be used to measure the output voltage from the first voltage divider circuit going to the pin 2, then when the voltage is more than the voltage available at pin3 it gives an output on pin1. we would have used a variable also at the second voltage divider circuit but to reduce stress we used a fixed resistor and the default reference voltage will be 2.5volts due to the power being 5volts so the two resistors reduced it to 2.5v, you could increase the voltage used in powering the whole circuit if you want but make sure your DC bulb can handle the voltage .
Then the resistor acts as an amplifier to amplify the power coming from the comparator due to the comparator being a low power type to power the bulb convenient my and to get something bright.
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